title: Aortic valve area, stroke volume, left ventricular hypertrophy, remodeling, and fibrosis in aortic stenosis assessed by cardiac magnetic resonance imaging: comparison between high and low gradient and normal and low flow aortic stenosis.
abstract: BACKGROUND
  Recent works using echocardiography suggested that low gradient (LG), low flow (LF) aortic stenosis (AS) has more pronounced left ventricular (LV) concentric remodeling, smaller LV cavity size, and more interstitial fibrosis compared with high gradient (HG) normal flow (NF) AS. Therefore, we evaluated the accuracy of echocardiographic measurements and compared remodeling and fibrosis in different types of AS by cardiac magnetic resonance (CMR).
  
  
  RESULTS
  A total of 128 patients (73±11 years of age; 75 men) with aortic valve area (AVA) <0.6 cm(2)/m(2) and ejection fraction >50% by echocardiography underwent CMR to measure planimetric AVA, phase-contrast indexed stroke volume, LV mass, and focal fibrosis. Using <40 mm Hg and indexed stroke volume <35 mL/m(2) by echocardiography as criteria for LG and LF, 69 (54%) patients were HG/NF, 28 (22%) HG/LF, 17 (13%) LG/NF, and 14 (11%) LG/LF AS. LV outflow tract area, indexed stroke volume, and AVA correlated well between echocardiography and CMR (r=0.7, 0.61, and 0.65, respectively; P<0.001 for all). By CMR, however, planimetric AVA was larger in LF/LG (0.54±0.08 cm(2)/m(2)) and LG/NF (0.61±0.08 cm(2)/m(2)) than in HG/LF (0.46±0.07 cm(2)/m(2); P<0.05) AS, and indexed LV mass was lower in LG/LF (75±12 g/m(2)) and LG/NF (81±18 g/m(2)) than in HG/LF (100±27 g/m(2); P<0.05) AS. All groups of AS had similar LV volumes, predominantly concentric hypertrophy remodeling, and similar amounts of focal fibrosis.
  
  
  CONCLUSIONS
  CMR confirmed overall accuracy of echocardiographic classification of AS but demonstrated that LG/LF and LG/NF AS have larger AVA, less LV hypertrophy, and similar focal fibrosis compared with HG/LF AS. This challenges the view that LG/LF AS is a more advanced state of AS.
authors.affiliation: Valvular Heart Disease Clinic, Division of Cardiology, Department of Cardiovascular Diseases, Cliniques Universitaires St. Luc, Woluwe St. Lambert, Belgium.
authors.forename: Gilles
authors.initials: G
authors.lastname: Barone-Rochette
authors.forename: Sophie
authors.initials: S
authors.lastname: Piérard
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Seldrum
authors.forename: Christophe
authors.initials: C
authors.lastname: de Meester de Ravenstein
authors.forename: Julie
authors.initials: J
authors.lastname: Melchior
authors.forename: Frédéric
authors.initials: F
authors.lastname: Maes
authors.forename: Anne-Catherine
authors.initials: AC
authors.lastname: Pouleur
authors.forename: David
authors.initials: D
authors.lastname: Vancraeynest
authors.forename: Agnes
authors.initials: A
authors.lastname: Pasquet
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Vanoverschelde
authors.forename: Bernhard L
authors.initials: BL
authors.lastname: Gerber
mesh_terms: D000368:Aged; D001021:Aortic Valve / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D001024:Aortic Valve Stenosis / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D001783:Blood Flow Velocity / Q000502:physiology*; D017548:Echocardiography, Transesophageal; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013318:Stroke Volume; D020257:Ventricular Remodeling
keywords: aortic valve stenosis; hypertrophy; magnetic resonance imaging; ventricular remodeling